I use frontline plus on my dogs and it works great on both fleas and ticks. One of my dogs has very sensitive skin and it is no problem. Though your vet will not tell you this here in the states, ivermectin, the same drug that is in the heart guard but in a larger dose given orally works for ticks.
Don't take it from me, just google the words ivermectin and ticks. Do some internet research on it so you can decide for yourself. The only thing is that with ivermectin, you cannot use comforts or any other oral flea meds that contain spinosad. Ivermectin (Ivermec) liquid is available at any feed store or online. A 50 ml bottle costs about $40 and lasts for a couple of years.